Document guiding device

ABSTRACT

A document guiding device for a document feeder. The document guiding device mainly comprises an inner wall, an outer wall and a lubricating element. The spatial area between the outer wall and the inner wall form a reversing passageway that accommodates a transiting document. The reversing passageway has a document inlet end and an outlet end both positioned on the same side of the document guiding device. The lubricating element is attached to the interior surface of the outer wall close to the area of contact between the front end of the document and the bend of the outer wall. The lubricating element facilitates the forward movement of the document so that the document is able to travel smoothly from the inlet to the outlet.

BACKGROUND OF INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to a document guiding device. More particularly, the present invention relates to the document guiding device of a document feeder capable of preventing the clogging of paper along the forward feeding path.

[0003] 2. Description of Related Art

[0004] Due to rapid progress in the electronic industry, many types of high performance computer systems are produced to be used almost anywhere. The development of high-speed processors and large capacity memory devices in recent years has also lead to the production of highly efficient image processors. Image processors including optical scanners and digital cameras are more frequently used.

[0005] In general, optical scanners can be divided into pocket scanners, sheet feed scanners, drum scanners and flatbed scanners, according to the document input method. For a sheet feed scanner, an optical resolution exceeding 600 dpi is currently achievable. Almost all sheet-feed scanners use a contact image sensor (CIS) scanning structure to reduce volume. Since each scanner occupies only a very small volume, the scanner is often carried along with a notebook computer.

[0006] To facilitate the scanning of a large number of documents, an automatic document feeder (ADF) is frequently used. When an automatic document feeder is used, documents are fed to a flatbed scanner or a sheet feed scanner one after the other and then sequentially scanned.

[0007] In general, a document guiding device is employed inside a document feeder to reduce overall volume of the feeder and facilitate user operation. The document guiding device turns an incoming document by 180 degrees so that both document inlet and document outlet are on the same side of the document feeder.

[0008]FIG. 1 is a schematic cross-sectional view of the document guiding device of a conventional document feeder. As shown in FIG. 1, the document guiding device 100 has a reversing passageway 102. The reversing passageway 102 is actually a spatial channel between an outer wall 104 and an inner wall 106. Furthermore, the outer wall 104 is constructed by joining an upper wall section 104 a and a lower wall section 104 b together. Similarly, the inner wall 106 is constructed by joining an upper wall section 106 a and a lower wall section 106 b together.

[0009] A document 116 is fed in the forward direction 122 into a document inlet port 108. Through the continuous rotation of a pair of rollers 112 and 114, the document 116 is pushed forward into the reversing passageway 102. As soon as the front end of the document 116 hits a document outlet port 110, the document 116 is expelled from the document guiding device 100 through a pair of rotating rollers 118 and 120. Since the inlet port 108 and the outlet port 110 are both on the same side, overall length of the document feeder is reduced.

[0010] However, aside from reducing the overall length of the document feeder, the height of the document feeder must be reduced as well. As shown in FIG. 1, the document guiding device 100 has a sharp bend along the reversing passageway 102.

[0011] When the document 116 moves forward along the reversing passageway 102 following the curve surface of the outer wall 104, the front end of the document 116 will encounter this sharp bend. Due to roughness and friction, the document 116 is easily clogged up somewhere close to the bend so that the document 116 can no longer come out through the outlet port 110. Hence, the document 116 is forced to wrinkle up inside the document guiding device, ultimately leading to some non-reversible damages. Moreover, the jammed document 116 must be removed before resuming the scanning operation.

SUMMARY OF INVENTION

[0012] Accordingly, one object of the present invention is to provide a document guiding device for a document feeder. The document guiding device prevents the jamming of documents inside the device and guides the transiting document out smoothly.

[0013] To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a document guiding device for a document feeder. The document guiding device mainly comprises of an inner wall, an outer wall and a lubricating element. The spatial area between the outer wall and the inner wall form a reversing passageway that accommodates a transiting document. The reversing passageway has a document inlet end and an outlet end both positioned on the same side of the document guiding device. The lubricating element is attached to the interior surface of the outer wall close to the area of contact between the front end of the document and the bend of the outer wall. Hence, the document can move forward smoothly from the inlet to the outlet without jamming inside the reversing passageway.

[0014] This invention also provides an alternative type document guiding device for a document feeder. The document guiding device mainly comprises an inner wall, an outer wall and a roller. The spatial area between the outer wall and the inner wall form a reversing passageway that accommodates a transiting document. The reversing passageway has a document inlet end and an outlet end both positioned on the same side of the document guiding device. The roller is attached to the interior surface of the outer wall close to the area of contact between the front end of the document and the bend of the outer wall. Hence, the document can move forward smoothly from the inlet to the outlet without jamming inside the reversing passageway.

[0015] In this invention, a lubricating element or a roller is attached to the contact area between the front end of the document and the bend inside the document guiding device. When the front end of a document touches the bend of the reversing passageway, the document is smoothly guided by the lubricating element or the roller. Ultimately, the document is able to turn around smoothly without clogging up the reversing passageway or causing any damage to the document.

[0016] It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,

[0018]FIG. 1 is a schematic cross-sectional view of the document guiding device of a conventional document feeder;

[0019]FIG. 2 is a schematic cross-sectional view of a document guiding device according to a first preferred embodiment of this invention; and

[0020]FIG. 3 is a schematic cross-sectional view of a document guiding device according to a second preferred embodiment of this invention.

DETAILED DESCRIPTION

[0021] Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

[0022]FIG. 2 is a schematic cross-sectional view of a document guiding device according a first preferred embodiment of this invention. As shown in FIG. 2, the document guiding device 200 has an outer wall 204, an inner wall 206 and a lubricating element 230.

[0023] The outer wall 204 is formed by joining an upper wall 204 a and a lower wall 204b together. Close to the junction between the upper wall 204 a and the lower wall 204 b, the upper wall 204 a gradually thickens in the direction of the inner wall 206. In other words, there is a step at the junction between the upper wall 204 a and the lower wall 204 b. The design of the outer wall 204 as an upper wall/lower wall assembly separable at the junction facilitates the removal of any document 21 6 jammed inside the reversing passageway 202 of the document guiding device 200. Furthermore, the protruding upper wall 204 a relative to the lower wall 204 b near the junction also facilitates a smooth transition of the document 216 from the upper wall 204 a to the lower wall 204 b. Hence, the frequency of clogging inside the reversing passageway 202 is minimized.

[0024] Similarly, the inner wall 206 is also formed by joining an upper wall 206 a and a lower wall 206 b. However, the inner wall 206 may also be manufactured as an integrative unit. Since the inner wall 206 has a U-shaped profile, forming the inner wall 206 from two separate pieces facilitates material transport and stacking before assembly.

[0025] The space between the outer wall 204 and the lower wall 206 forms a turnaround passageway 202 suitable for the passage of a document. The reversing passageway 202 has an inlet port 208 and an outlet port 210 on the same side of the document guiding device 200. The upper wall 204 a extends from the junction between the upper wall 204 a and the lower wall 204 b towards the inlet end 208. Similarly, the lower wall 204 b extends from the junction between the upper wall 204 a and the lower wall 204 b towards the outlet end 210.

[0026] The lubricating element 230 is attached to the interior surface of the lower wall 204 next to the junction. The lubricating element 230 is a thin layer of extra-smooth material such as Teflon or Mylar (a polyresin film). To reduce friction and facilitate the smooth transition of the document inside the passageway 202, the lubricating element 230 is attached close to the contact region between the lower wall 204 b and the front end of the document 216. Preferably, the lubricating element 230 is positioned at the point of first contact between the document 216 and the sharp bend along the reversing passageway 202. In other words, the document 216 is able to turn smoothly around the bend without clogging up the passageway 202. Furthermore, the lubricating element 230 has a thickness smaller than the difference in step height between the upper wall 204 a and the lower wall 204 b. In addition, one end of the lubricating element 230 is preferably attached to the junction between the upper wall 204 a and the lower wall 204 b so that the possibility of a document caught by the element 230 is minimized.

[0027] A pair of transmission rollers 212, 214 may also be installed near the inlet port 208 to facilitate the entrance of document into the reversing passageway 202.

[0028] Similarly, a pair of transmission rollers 218, 220 may also be installed near the outlet port 210 to facilitate the emission of document from the document guiding device 200.

[0029] To turn a document 216 around using the document guiding device 200, the document 216 is slipped in through the document inlet 208. The rollers 212, 214 drag the document 216 into the reversing passageway 202 in a forward direction 222. Continuous rotation of the rollers 212, 214 brings the document 216 forward. When the front end of the document 216 bypasses the upper wall 204 a to contact the lower wall 204 b, the presence of lubricating element 230 facilitates a smooth transition of the document around the bend in the passageway 202. Thereafter, the document 216 is pushed forward to the rollers 218, 220. The rollers 218, 220 rotate and hence push the document 216 out through the outlet port 210.

[0030] In the first embodiment, the lubricating element 230 is attached to the interior surface of the lower wall 204 b close to the bend of the passageway 202. However, the scope of this invention is not limited to the attachment of a lubricating element as such. Alternative arrangements capable of achieving the same goal include polishing the interior wall of the lower wall 204 b or material having a smooth surface may be used to manufacture the lower wall 204 b.

[0031]FIG. 3 is a schematic cross-sectional view of a document guiding device according a second preferred embodiment of this invention. As shown in FIG. 3, the document guiding device 300 has an outer wall 304, an inner wall 306 and a roller 330.

[0032] The outer wall 304 is formed by joining an upper wall 304 a and a lower wall 304 b together. Close to the junction between the upper wall 304 a and the lower wall 304 b, the upper wall 304 a gradually thickens in the direction of the inner wall 306. In other words, there is a step at the junction between the upper wall 304 a and the lower wall 304 b.

[0033] Similarly, the inner wall 306 is also formed by joining an upper wall 306 a and a lower wall 306 b. However, the inner wall 306 may also be manufactured as an integrative unit.

[0034] The space between the outer wall 304 and the lower wall 306 forms a turnaround passageway 302 suitable for the passage of a document. The reversing passageway 302 has an inlet port 308 and an outlet port 310 on the same side of the document guiding device 300. The upper wall 304 a extends from the junction between the upper wall 304 a and the lower wall 304 b towards the inlet end 308. Similarly, the lower wall 304 b extends from the junction between the upper wall 304 a and the lower wall 304 b towards the outlet end 310.

[0035] The roller 330 is attached to the interior surface of the lower wall 304 close to the junction. The roller 330 rotates in a direction that drags a document 316 towards the outlet port 310. According to the forward direction 322 in the second embodiment (shown in FIG. 3), the roller 330 rotates in a clockwise direction. On the contrary, if the document 316 moves forward in a direction opposite to 322, the roller 330 will rotate in an anti-clockwise direction. To facilitate the smooth transition of the document 316 inside the passageway 302, the roller 330 is attached close to the contact region between the lower wall 304 b and the front end of the document 316. Preferably, the roller 330 is positioned at the point of first contact between front end of the document 316 and the sharp bend along the reversing passageway 302. In other words, the document 316 is able to turn smoothly around the bend without clogging up the passageway 302. Furthermore, the top of the roller 330 is preferably at a level smaller than the difference in step height between the upper wall 304 a and the lower wall 304 b.

[0036] In addition, a pair of transmission rollers 312, 314 may also be installed near the inlet port 308 to facilitate the entrance of document into the reversing passageway 302. Similarly, a pair of transmission rollers 318,320 may also be installed near the outlet port 310 to facilitate the emission of document from the document guiding device 300.

[0037] To turn a document 316 around using the document guiding device 300, the document 316 is slipped in through the document inlet 308. The rollers 312, 314 drag the document 316 into the reversing passageway 302 in a forward direction 322.

[0038] Continuous rotation of the rollers 312, 314 brings the document 316 forward. When the front end of the document 316 bypasses the upper wall 304 a to contact the lower wall 304 b, the presence of the roller 330 lowers friction and facilitates the passage of document around the bend of the passageway 302. Thereafter, the document 316 is pushed forward to the rollers 318, 320. The rollers 318, 320 rotate and hence push the document 316 out through the outlet port 310.

[0039] In summary, a lubricating element or a roller is attached to the contact area between the front end of a document and a curve bend inside the document guiding device. When the front end of a document contacts the bend of the reversing passageway, the document is smoothly guided by the lubricating element or the roller. Consequently, the document turns around smoothly without clogging up the reversing passageway or causing any damage to the document.

[0040] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

1. A document guiding device for a document feeder, comprising: an inner wall; an outer wall, wherein the space between the outer wall and the inner wall forms a reversing passageway, the reversing passageway has an inlet port and an outlet port both on the same side of the document guiding device; and a lubricating element attached to the interior surface of the outer wall, wherein the lubricating element is positioned close to the contact area between the front end of a document and the bend of the outer wall so that a document may move through the passageway smoothly without jamming.
 2. The document guiding device of claim 1, wherein the outer wall is a separable assembly formed by joining an upper wall and a lower wall together.
 3. The document guiding device of claim 2, wherein one end of the upper wall extends from the junction between the upper wall and the lower wall towards the inlet port and one end of the lower wall extends from the junction between the upper wall and the lower wall towards the outlet port.
 4. The document guiding device of claim 2, wherein the lubricating element is attached to lower wall portion of the outer wall.
 5. The document guiding device of claim 4, wherein the upper wall gradually thickens towards the junction so that the upper wall protrudes towards the inner wall beyond the upper surface of the attached lubricating element.
 6. The document guiding device of claim 1, wherein the lubricating element is fabricated using a surface-smooth material.
 7. The document guiding device of claim 1, wherein material constituting the lubricating element is selected from a group consisting of Teflon and polyresin such as Mylar.
 8. The document guiding device of claim 1, wherein the inlet port further includes a pair of transmission rollers for dragging a document into the reversing passageway.
 9. The document guiding device of claim 1, wherein the outlet port further includes a pair of transmission roller for expelling a document out of the reversing passageway.
 10. A document guiding device for a document feeder, comprising: an inner wall; an outer wall, wherein the space between the outer wall and the inner wall forms a reversing passageway, the reversing passageway has an inlet port and an outlet port both on the same side of the document guiding device; and a roller attached to the interior surface of the outer wall, wherein the roller is positioned close to the contact area between the front end of a document and the bend of the outer wall so that a document may move through the passageway smoothly without jamming.
 11. The document guiding device of claim 10, wherein the outer wall is a separable assembly formed by joining an upper wall and a lower wall together.
 12. The document guiding device of claim 11, wherein one end of the upper wall extends from the junction between the upper wall and the lower wall towards the inlet port and one end of the lower wall extends from the junction between the upper wall and the lower wall towards the, outlet port.
 13. The document guiding device of claim 11, wherein the roller is attached to lower wall portion of the outer wall.
 14. The document guiding device of claim 13, wherein the upper wall gradually thickens towards the junction so that the upper wall protrudes towards the inner wall beyond the upper surface of the attached roller.
 15. The document guiding device of claim 10, wherein the roller rotates in a direction that moves the document towards the outlet port.
 16. The document guiding device of claim 10, wherein the inlet port further includes a pair of transmission rollers for dragging a document into the reversing passageway.
 17. The document guiding device of claim 10, wherein the outlet port further includes a pair of transmission rollers for expelling a document out of the reversing passageway. 